TWI382067B - Infrared low-emmisive paint and method for manufacturing the same - Google Patents

Description

Infrared low emissivity paint and method of forming same

This invention relates to an infrared low emissivity coating, and more particularly to its binder composition.

Since the 21st century, energy consumption has increased dramatically in the world, and energy conservation has become the consensus of the whole world. In the industry, thermal insulation coatings are of great significance at this moment. Thermal insulation is mainly to block the heat loss of the boiler fittings themselves, and on the other hand, to protect workers. The heat source generally propagates in the form of convection, radiation, and conduction. The higher the proportion of infrared radiation in the higher temperature environment, the more important the energy saving of radiant heat. There are three ways to reduce infrared radiation: one, changing the infrared radiation characteristics of the target, that is, the emissivity distribution of the target, second, reducing the intensity of the infrared radiation, and third, adjusting the propagation path of the infrared radiation. The development of low emissivity coatings on the target can change the infrared radiation characteristics and reduce the intensity of infrared radiation, which is a simple and effective method of thermal insulation.

The combustion system or high-temperature objects will emit a large amount of radiant heat. The heat radiated by the heat radiator will be absorbed by the equipment and the water pipe group, and will be re-radiated after absorption. Therefore, the technology reduces the heat radiation loss and the saving of the industrial boiler and the pipe fittings. Fuel, protects the life of medium carbon steel with high surface temperature, reduces the heat loss by spraying low emissivity coatings, reduces the input of more fuel, and achieves the goal of reducing CO ₂ gas production and system energy conservation.

The development of low emissivity coatings originated from military infrared stealth applications. In the first phase, the United States Air Force commissioned Honeywell to conduct research on diffuse reflective infrared reflective coatings in 1967. Second order Paragraph, from the late 1970s to the mid-1980s, the US Army Armaments Command conducted many studies on mid-range and far-infrared stealth coatings and suitable binders. The Nntick Research and Development Laboratory and the Beivoir Research and Development Center also have low emissivity thermal stealth coatings. Do a lot of research work. After the mid-1980s, Western countries were involved in the study of hot stealth coatings. Germany, Britain, France, Japan, Canada, and Australia all reported information on this aspect of work during this period. A report on the development of thermal stealth coatings published by the Australian Department of Defense Materials Laboratory in 1984 attracted widespread attention. According to experts, the development of thermal stealth coatings has entered the active secret development stage from the initial exploration. The first-stage emissivity is higher than 0.5, and the second-generation infrared stealth coating in the third stage is mainly strengthened in the development of new binders and pigments. The fourth stage is due to the maturity stage of the second generation of infrared stealth coatings. The coatings use polymers with high infrared transparency (possibly butyl rubber, Kraton resin) and coloring pigments (possibly including cadmium sulfide, iron oxide, etc.), followed by a small amount of metal. Pigments, which have been commercialized, have a radioactivity of less than 0.5. Aestra is one of the manufacturers in the United States, and the No. 5 formula in Table 1 is its prototype.

Table 2 lists the low emissivity coating patents and efficacy matrix. The coating patents claim that the emissivity is mostly higher than 0.5. The main methods are to improve the pigment filling technology, the multilayer structure stack design, or to do the physical vapor deposition to make the low radiation window. (low emissivity window) application, in which the physical vapor deposition method has an emissivity of up to 0.3, the physical vapor deposition method has the disadvantages of high cost and on-site coating, and has few functional groups and infrared transmittance for the binder. The nature of the matter is further explored. Only US3189576 mentions the use of silicon-bonded oxime resin as a binder and US4131593 for nuclear flash protection. Now the raw material is high in antimony resin (special type resin, >NT $1000/kg). Since the emissivity of the resin is not low, it is necessary to add a high proportion of metal powder to reduce the emissivity, and the price of aluminum paste. It does not lose resin, so the coating price is very high, and the emissivity can only reach 0.45 or more.

In summary, the foreign countries have discovered the situation. First, foreign infrared stealth coatings have been colored, but the colors are not rich enough and practical. Second, foreign research and development of low emissivity coatings for visible light, infrared light and microwave, but compatible Sexuality is still not fully resolved; third, most of it is applied to the military, but it is rarely applied to the outer surface of industrial boilers.

Domestically, the research history of infrared low emissivity coatings is very short and limited to military research units. Because this technology involves the defense of stealth stealth technology (including missiles, stealth fighters, aircraft, ground equipment, camouflage clothing), advanced countries are extremely confidential, so the research and development situation is less disclosed, compared to the rapid development of infrared stealth There is still a considerable gap in technology. Although it does not develop national defense military, it is very important to save energy in Minsheng. However, there are not many such products in China, the color is only gray, the infrared emissivity is higher than 0.5, and it is less used in industrial energy conservation. Tsinghua University has discussed the application of nano-sized silver particles and inorganic binders on films. The infrared emissivity is about 0.04. In addition, the transparency of double-layer polymer matrix is also affected by low emissivity. The infrared emissivity is higher than 0.7. Domestic schools discuss the development of conductive polymer materials. Although there are some scattered research and development in the academic world, they are not too expensive and have poor physical properties. Therefore, the emissivity is too high and it is difficult to obtain industrial energy-saving applications. In summary, domestic infrared low emissivity coatings should be practical, energy-saving, environmentally friendly, and color-oriented, and there is still a long way to go.

The invention provides a method for forming an infrared low emissivity paint, which comprises dissolving 10 to 30 parts by weight of a multicomponent copolymer, 70 to 90 parts by weight of a double bond monomer and an acrylate, and 0.1 to 0.3 parts by weight of an initiator. At 100 After heating to 150 parts by weight of the solvent, the double bond monomer and the acrylate are grafted to the multicomponent copolymer to form a binder; and 100 parts by weight of the binder, 10 to 30 parts by weight of the metal filler, 0.1 to 1 part by weight of the colored filler, 5 to 10 parts by weight of the semiconductor filler, and 0.5 to 1 part by weight of the auxiliary agent are uniformly mixed to form an infrared low emissivity filler.

The present invention also provides an infrared low emissivity coating comprising a binder comprising 10 to 30 parts by weight of a multicomponent copolymer and 70 to 90 parts by weight of a double bond monomer and an acrylate graft copolymerized; and 10 to 30 The metal filler by weight, 0.1 to 1 part by weight of the colored filler, 5 to 10 parts by weight of the semiconductor filler, 0.5 to 1 part by weight of the auxiliary agent and 100 parts by weight of the binder are uniformly mixed.

Adhesives are the main film-forming substances of coatings and are one of the main factors that mainly affect the emissivity of coatings. At least 60% of the absorption capacity of the thermal infrared band of the coating depends on the binder. At present, more research is on pigments and fillers, while binders are less inked, and it is difficult to obtain effective material information because of the principle of non-disclosure of military applications. In addition, in addition to the general requirements of physical and mechanical properties, construction performance, and low cost, the binder should also have low infrared emissivity or high transparency. Generally used in paint binder resin, the transparency is low and the emissivity is high in the wavelength of 8~14μm. Even the excellent infrared transparent Kraton resin has an average emissivity of 0.84 in the far infrared band. Therefore, the present invention proposes a low emissivity binder to overcome the high emissivity of the coating. In this case, it is proposed to replace the special-purpose resin with a lower-cost, lower emissivity binder, which is not only cheap, high-temperature resistant, and the emissivity can be less than 0.2, so that the low emissivity coating The success has been achieved, and the low emissivity products that were previously only available in the more expensive physical vapor deposition (vacuum conditions) have been significantly reduced, so that large areas can be realized in the future, especially in automotive and construction applications.

First, the initiator is dissolved in a solvent and heated to form a radical. Suitable starters for use in the present invention are thermal starters such as azo or peroxides. Azos such as 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2' - dimethyl 2,2'-azobis(2-methylpropionate), 2,2-azobisisobutyronitrile (hereinafter referred to as AIBN), 2, 2-azobis(2-methylisobutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile) 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis[N-2-propyl-2-methylpropionamide] (2,2'-azobis[N-(2-propenyl)-2 -methylpropionamide]), 1-[(cyano-1-methylethyl)-azo]formamide, 2,2'-azo Bis (N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methyl) (2,2'-azobis (N-cyclohexyl-2-methylpropionamide), or other suitable azo-based initiator; peroxides include benzoyl peroxide, 1,1-bis(tert-butylperoxycyclohexane), 2,5-bis (t-butyl) Oxy)-2,5-dimethylcyclohexane (2,5-bis (tert-butylperoxy)-2,5-dimethylcyclohexane), 2,5-bis(t-butylperoxy)-2, 5-Dimethyl-3-cyclohexyne (2,5-bis (tert-butylperoxy)-2,5-dimethyl-3-cyclohexyne), bis(1-(t-butylperoxy)-1- Bis(1-(tert-butylpeorxy)-1-methy-ethyl)benzene, tert-butyl hydroperoxide, tert-butyl peroxide (tert- Butyl peroxide), tert-butyl peroxybenzoate, cumene hydroperoxide, cyclohexanone peroxide, difenyl peroxide Peroxide), lauroyl peroxide, or other suitable peroxide. The above thermal initiators may be used in combination or in combination, depending on the needs. The type and amount of the initiator can determine the molecular weight and degree of polymerization of the polymer.

Suitable solvents can be xylene, toluene, tetrahydrofuran, n-butanol, methyl ethyl ketone. In the subsequent polymerization, the action of the solvent includes dissolving and dispersing the reaction material, promoting uniform contact of the reactants, controlling temperature, transferring heat, promoting bond transfer, and controlling molecular weight.

Next, the multicomponent copolymer, the double bond monomer, and the acrylate are dissolved in the above radical-containing solution, and then heated to graft the double bond monomer and the acrylate to the multicomponent copolymer to form a binder. The double bond monomer can be styrene, polybutadiene, ethylene, propylene, acrylonitrile, or a combination thereof. The acrylate may be acrylic acid, methyl methacrylate, methyl acrylate, butyl acrylate, hexyl acrylate or a combination thereof. Multicomponent copolymers are ethylene-propylene-diene Polymer (EPDM), acrylonitrile-butadiene-styrene copolymer (ABS), or a mixture of the foregoing.

In the above polymerization reaction, the weight of the initiator is about 0.1% to 0.3% by weight of the total reactant, the weight of the multicomponent copolymer is about 10% to 30% by weight of the total reactant, and the double bond monomer and the acrylate account for about the reaction. The total weight of the material is between 70% and 90%, and the weight of the solvent is about 1 to 1.5 times the total weight of the reactant. The above polymerization temperature is between 80 ° C and 120 ° C, and the reaction time is 8 to 10 hours.

Then, the above-formed binder is uniformly mixed with a metal filler, a colored filler, a semiconductor filler, and an auxiliary agent to complete the infrared low emissivity paint of the present invention. The metal filler includes sheet aluminum powder, reduced iron powder, or silver powder. The role of the metal filler is to increase the reflection of infrared light, increase the thermal conductivity, and improve the temperature resistance of the coating, and the weight ratio of the adhesive to the metal filler is between 100:10 and 100:30. When the proportion of the metal filler is less than the above range, it will be less resistant to high temperatures and increase the emissivity, but when the proportion of the metal filler is larger than the above range, the cost may be increased and the emissivity may not be lowered. Colored fillers include metal oxides and hydroxides, sulfides, selenides, inorganic salts, and organic pigments. The coloring filler acts to increase the aesthetics and provide infrared transparency, and the weight ratio of the adhesive to the coloring filler is between 100:0.1 and 100:1. When the proportion of the colored filler is less than the above range, it will be easily faded, but when the proportion of the colored filler is larger than the above range, the cost may be increased. The semiconductor filler includes indium tin oxide, antimony tin oxide, or aluminum-doped zinc oxide. The role of the semiconductor filler is to increase the conductivity, reduce the emissivity, increase the visible light transmittance, and increase the infrared reflectance, and the weight ratio of the adhesive to the semiconductor filler is between 100:5 and 100:10. When the semiconductor is filled When the proportion of the material is less than the above range, the emissivity is remarkably improved, but when the proportion of the semiconductor filler is larger than the above range, the emissivity is also increased. The adjuvant includes an initiator, a decane coupling agent, a wetting and dispersing agent, or a bridging agent. The auxiliary agent functions as adhesion to the substrate, dispersibility between the components of the coating, structural stability, and the weight ratio of the adhesive to the auxiliary agent is between 100:0.5 and 100:1. When the proportion of the auxiliary agent is less than the above range, it will be agglomerated, layered, loose in structure, easy to fall off, and difficult to form a film. However, when the proportion of the auxiliary agent is larger than the above range, the viscosity may be too high to be difficult to construct and increase. cost.

The infrared low emissivity coating formed by the above method can coat the metal and non-metal surfaces of the heat preservation equipment, pipes, boilers and pipe fittings, can reduce the infrared radiant heat of the thermal system, reduce the heat loss of the system, or be coated in construction, automobile or other fields. (For example: heating in a cold environment in winter, or using air conditioning in a hot summer environment), passively controlling the propagation of thermal energy to achieve energy-saving loss performance. The formulation of such a coating can greatly reduce the emissivity ε of the wavelength of 2 to 22 μm to less than 0.2 by using the metal micropowder and the modified binder. The modified binder formulation has infrared transparency and good physical properties. When the multicomponent copolymer in the reactant is the EPDM series, its infrared emissivity is about 0.2. When the multicomponent copolymer in the reactant is the ABS series, its infrared emissivity is about 0.13.

In order to more clearly illustrate the features of the present invention, the following examples are illustrated.

[Examples] Example 1

0.1 g of AIBN was dissolved in 100 mL of xylene, and heated to 80 ° C to form a radical. In addition, 30 g of EPDM (S. Prosper Corp. (H01-1002)), 70 g of acrylonitrile (SHOWA (Showa)), or 70 g of butyl acrylate (SHOWA (Showa)) were added to the solvent containing free radicals. The reaction was carried out at 80 ° C for 10 hours to form a binder. After the above-mentioned binder was warmed to room temperature, 20 g of a sheet metal aluminum filler (Al: 83% composition, S. Prosper Corp. (FA1-02)), and 1 g of a coloring filler (Iron chromium oxide hematite, S. Prosper Corp. (I-G223)), 9 g of semiconductor filler (ITO: In ₂ O ₃ :SnO ₂ =90:10 wt%, S. Prosper Corp. (D01-9000)), and 0.5 g of decane coupling agent (S. Prosper Corp. (G02-1002)), after uniformly stirring and mixing, forms the infrared low emissivity paint of the present invention. After the coating material was spin-coated on the substrate, the coating was heated and dried to remove the solvent, that is, a film having a thickness of 0.2 mm and an area of 100 cm ^{2 was} formed, and the infrared ray ratio was 0.2.

Example 2

Similar to Example 1, the difference was that the EPDM of the reactant was replaced with ABS. The finally formed film had a thickness of 0.1 mm, an area of 100 cm ² , and an infrared ray emissivity of 0.13.

The present invention has been disclosed in several embodiments, and is not intended to limit the invention, and any one of ordinary skill in the art can make any changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

Claims (17)

A method for forming an infrared low emissivity paint comprising: dissolving 10 to 30 parts by weight of a multicomponent copolymer, 70 to 90 parts by weight of a double bond monomer and an acrylate, and 0.1 to 0.3 parts by weight of an initiator in 100 After heating to 150 parts by weight of the solvent, the double bond monomer and the acrylate are grafted to the multicomponent copolymer to form a binder; and 100 parts by weight of the binder, 10 to 30 parts by weight of the metal filler 0.1 to 1 part by weight of the colored filler, 5 to 10 parts by weight of the semiconductor filler, and 0.5 to 1 part by weight of the auxiliary agent are uniformly mixed to form an infrared low emissivity filler. The method of forming an infrared low emissivity paint according to claim 1, wherein the multicomponent copolymer comprises EPDM, ABS, or a mixture thereof. The method for forming an infrared low emissivity paint according to claim 1, wherein the initiator comprises an azo compound or a peroxide. The method for forming an infrared low emissivity paint according to claim 1, wherein the double bond monomer comprises styrene, polybutadiene, ethylene, propylene, acrylonitrile, or a combination thereof. The method for forming an infrared low emissivity paint according to claim 1, wherein the acrylate comprises acrylic acid, methyl methacrylate, methyl acrylate, butyl acrylate, hexyl acrylate or a combination thereof. The method for forming an infrared low emissivity paint according to claim 1, wherein the metal filler comprises a sheet aluminum powder, a reducing iron powder, or a silver powder. The method for forming an infrared low emissivity paint according to claim 1, wherein the colored filler comprises a metal oxide and a hydroxide, a sulfide, a selenide, an inorganic salt, and an organic pigment. The method for forming an infrared low emissivity paint according to claim 1, wherein the semiconductor filler comprises indium tin oxide, antimony tin oxide, or aluminum-doped zinc oxide. The method for forming an infrared low emissivity paint according to claim 1, wherein the auxiliary agent comprises a starter, a decane coupling agent, a wetting and dispersing agent, or a bridging agent. An infrared low emissivity coating comprising: a binder comprising 10 to 30 parts by weight of a multicomponent copolymer and 70 to 90 parts by weight of a double bond monomer and an acrylate graft copolymerized; and 10 to 30 parts by weight The metal filler, 0.1 to 1 part by weight of the colored filler, 5 to 10 parts by weight of the semiconductor filler, 0.5 to 1 part by weight of the auxiliary agent and 100 parts by weight of the binder are uniformly mixed. The infrared low emissivity paint of claim 10, wherein the multicomponent copolymer comprises EPDM, ABS, or a mixture thereof. The infrared low emissivity coating of claim 10, wherein the double bond monomer comprises styrene, polybutadiene, ethylene, propylene, acrylonitrile, or a combination thereof. The infrared low emissivity paint according to claim 10, wherein the acrylate comprises acrylic acid, methyl methacrylate, methyl acrylate, butyl acrylate, hexyl acrylate or a combination thereof. The infrared low emissivity paint according to claim 10, wherein the metal filler comprises a sheet aluminum powder, a reducing iron powder, or a silver powder. The infrared low emissivity paint according to claim 10, wherein the colored filler comprises a metal oxide and a hydroxide, a sulfide, a selenide, an inorganic salt, and an organic pigment. The infrared low emissivity paint according to claim 10, wherein the semiconductor filler comprises indium tin oxide, antimony tin oxide, or aluminum-doped zinc oxide. The infrared low emissivity paint according to claim 10, wherein the auxiliary agent comprises an initiator, a decane coupling agent, a wetting and dispersing agent, or a bridging agent.